Electron-beam lithography for photonic waveguide fabrication: Measurement of the effect of field stitching errors on optical performance and evaluation of a new compensation method

A method for stitching error compensation in electron beam lithography by multipass writing of the pattern in the areas spanning the field boundaries is described. This method does not require reducing the write current or changing beam dwell time and was used to correct artificial stitching errors which were deliberately introduced in a layout. SOI-based photonic waveguides with intentional stitching errors of predefined amplitudes and orientation were fabricated. The number of the errors along the waveguides was chosen to produce a measurable optical effect. A corrected version of the same layout was fabricated on the same chip. The optical losses were measured for both the TE and TM polarizations and compared to the results of finite difference time domain simulations. Measurements of optical losses for the waveguides after correction show a clear improvement.